chore(internal): reduce CI branch coverage

Author: stainless-app[bot]

.github/workflows/ci.yml

@@ -2,13 +2,12 @@ name: CI
 
 on:
   push:
-    branches-ignore:
-      - 'generated'
-      - 'codegen/**'
-      - 'integrated/**'
-      - 'preview-head/**'
-      - 'preview-base/**'
-      - 'preview/**'
+    branches:
+      - main
+  pull_request:
+    branches:
+      - main
+      - next
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}